Unequal Binning for Spectroscopy

[PeterO]

Hi,

I'm a beginner in astronomy; keen to get started in spectroscopy; and with a background in scientific instruments. I'm looking to set up a portable observing station to take to sites by train. The system I'm considering is an ED80T with HEQ5 or HEQ6 tripod and an Alpy 600 spectroscope with reflecting slit guide. The sensitivity might be improved without compromising the resolution using a camera with unequal binning, ie binning in one axis only so I'm looking for a CCD camera that allows for example 1x3 or 1x4 or more binning; or has elongated slot like pixels (unlikely but ideal). I'd also be interested if anyone can tell me whether the commonly available spectra processing programs like RSPEC or IRIS carry out this kind of function, though a post processing solution would be noisier.

Be glad to hear comment on how well such a system may or may not perform and keen to find a camera with unequal binning.

Thanks Peter

[andrew s]

Peter, I think most people use 1x1 binning on camera and allow the software (I use ISIS) to do the optimal spectra extraction binning across the direction of dispersion. Keeping the camera at 1x1 binning allows the removal of bad pixels and makes sky subtraction simpler. 1x1 also help if your spectra are not accuratly aligned with the axis of the CCD as the software can mage the corrections.

Hope this helps.

Regards Andrew

[Merlin66]

Welcome to SGL!

I agree with Andrew.

Depending on plate scale 1 x1 or 2 x 2 then vertically binning is the way to go.

Any cooled mono CCD you can afford would be the answer....ATik16/ ATiK314 etc.

Do you have any specific programs in mind for your ALPY?? What will you use for guiding? Lodestar?

VSpec/ ISIS/ SPCAude/ RSpec can all assist you with the processing.

On the astronomical spectroscopy Yahoo Group (see below) we have the SimSpec V4 spreadsheet available to allow you to assess the results of various telescope/ spectroscope/ camera options.

[PeterO]

Thank you both for your feedback and the excellent links, I've just joined the astronomical spectroscopy Yahoo Group and looked at Ken Harrison's simulator (I have both his books and have read them cover to cover).

For the main camera I'll be using the ATIK314l+ camera as it is economical and well characterised. Guiding will be with the Orion Autoguider and Shelyak guiding module. A neon lamp for calibration.

My aim is to join the AAVSO citizen science group and follow their training program to eventually help with examining novae, supernovae and cataclysmic variables (I'm also curious to see if I can observe the occultation of each star in the binary spectroscopically) I think that's about as far as the resolution of an ALPY will take me. Would it also be possible to see the gravitational redshift in stars approaching a black hole? Being very new to astronomy I have no idea if that is a reasonable ambition? I'm not at all certain that an 80mm telescope with an R600 spectrometer will be adequate to work with the AAVSO group, but I'm greatly inspired by Jack Martin, Christian Buil and Olivier Thizy who demonstrate that a great deal can be done with 80mm telescopes and low resolution diffraction gratings.

Thanks to both of you for your advice.